The invention relates to a washing machine (this expression including also a washing machine having dryer function) comprising a recirculation circuit.
EP 1 204 792 B1 discloses a washing machine having a recirculation circuit. An inlet of a draining circuit of the washing machine is connected to a sump, wherein a check valve is arranged between the sump and the inlet of the draining circuit. The check valve shuts off the sump from the draining circuit during a washing cycle. An inlet of the recirculation circuit is located at the sump and upstream the check valve.
It may occur that valves as described above are not perfectly watertight during a washing operation. The valve may partially be opened due to variations of pressure inside the tub and/or of movements of the tub or drum. In particular at the beginning of a washing cycle, when a detergent like a powder detergent is not fully dissolved in the washing water, this detergent can accumulate at a lower portion of the tub due to gravity. Such undissolved detergent can enter the draining circuit through a partially opened valve with the risk of reducing the washing effect and/or of obstructing the draining pump.